Sundance, WY frost dates
Last spring frostMay 21median date
First fall frostSep 25median date
Growing season127 daysfrost-free
Hardiness zone4bZone 4b
How Sundance compares
- In 8 years out of 10, the last spring frost in Sundance falls between May 9 and June 5, a 27-day window. The first fall frost falls between September 7 and October 8.
- The median last frost is the same as the Wyoming median of May 21.
- Its 127-day growing season is longer than 53% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 13 days later than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 179 nights a year at or below 32°F.
- Compared with Rapid City, SD, 97 km away, the last frost here is 18 days later than there and the growing season is 31 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 9 |
| 50% (median) | May 21 |
| 10% (safe for tender plants) | June 5 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 25 |
| 90% (late) | October 8 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Sundance, WY
Sundance, WY frost dates — last frost May 21, first frost Sep 25, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 26 to Mar 12Transplant outside: Apr 23 to May 7
Start indoors: Mar 12 to Mar 26Transplant outside: Jun 4 to Jun 18
Start indoors: Mar 12 to Mar 26Transplant outside: Jun 4 to Jun 18
Start indoors: Mar 26 to Apr 9Transplant outside: May 28 to Jun 11
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 30 to May 14Sow outdoors: Apr 23 to May 28Plant for fall: Jul 31 to Aug 28
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 23 to May 7Sow outdoors: Apr 23 to May 7Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 26 to Apr 9Transplant outside: May 7 to May 21Plant for fall: Jun 19 to Jul 10
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 30 to May 14Plant for fall: Jun 19 to Jul 10
Start indoors: Mar 26 to Apr 9Transplant outside: May 7 to May 21Plant for fall: Jun 19 to Jul 10
Start indoors: Apr 9 to Apr 23Transplant outside: Jun 11 to Jun 25Sow outdoors: Jun 11 to Jun 25
Start indoors: Apr 9 to Apr 23Transplant outside: May 28 to Jun 11
Sow outdoors: Apr 9 to Apr 30Plant for fall: Jul 3 to Jul 24
Sow outdoors: Apr 9 to Apr 30Plant for fall: Jul 31 to Aug 21
Sow outdoors: Apr 16 to May 28Plant for fall: Aug 14 to Sep 4
Start indoors: Apr 23 to Apr 30Transplant outside: Jun 4 to Jun 11Sow outdoors: May 28 to Jun 11Plant for fall: Jul 10 to Jul 24
Start indoors: Apr 23 to Apr 30Sow outdoors: May 28 to Jun 11Plant for fall: Jul 17 to Jul 31
Start indoors: Apr 23 to Apr 30Sow outdoors: May 28 to Jun 11
Start indoors: Apr 23 to Apr 30Transplant outside: Jun 4 to Jun 18
Sow outdoors: Apr 30 to May 28Plant for fall: Jul 3 to Jul 17
Sow outdoors: Apr 30 to May 28Plant for fall: Jul 17 to Jul 31
Sow outdoors: Apr 30 to May 21
Sow outdoors: May 7 to Jun 4Plant for fall: Jul 17 to Jul 31
Sow outdoors: May 7 to May 28Plant for fall: Jul 31 to Aug 21
Sow outdoors: May 28 to Jun 18Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 28 to Jun 11
Transplant outside: Jun 4 to Jun 25
Plant for fall: Sep 11 to Oct 16
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Sundance, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 26 – Mar 12 | Apr 23 – May 7 | — | — |
| Peppers | Mar 12 – Mar 26 | Jun 4 – Jun 18 | — | — |
| Eggplant | Mar 12 – Mar 26 | Jun 4 – Jun 18 | — | — |
| Tomatoes | Mar 26 – Apr 9 | May 28 – Jun 11 | — | — |
| Lettuce | Mar 26 – Apr 9 | Apr 30 – May 14 | Apr 23 – May 28 | Jul 31 – Aug 28 |
| Kale | Mar 26 – Apr 9 | Apr 23 – May 7 | Apr 23 – May 7 | Jul 17 – Aug 7 |
| Broccoli | Mar 26 – Apr 9 | May 7 – May 21 | — | Jun 19 – Jul 10 |
| Cabbage | Mar 26 – Apr 9 | Apr 30 – May 14 | — | Jun 19 – Jul 10 |
| Cauliflower | Mar 26 – Apr 9 | May 7 – May 21 | — | Jun 19 – Jul 10 |
| Okra | Apr 9 – Apr 23 | Jun 11 – Jun 25 | Jun 11 – Jun 25 | — |
| Basil | Apr 9 – Apr 23 | May 28 – Jun 11 | — | — |
| Peas | — | — | Apr 9 – Apr 30 | Jul 3 – Jul 24 |
| Spinach | — | — | Apr 9 – Apr 30 | Jul 31 – Aug 21 |
| Radishes | — | — | Apr 16 – May 28 | Aug 14 – Sep 4 |
| Cucumbers | Apr 23 – Apr 30 | Jun 4 – Jun 11 | May 28 – Jun 11 | Jul 10 – Jul 24 |
| Zucchini & Summer Squash | Apr 23 – Apr 30 | — | May 28 – Jun 11 | Jul 17 – Jul 31 |
| Winter Squash & Pumpkins | Apr 23 – Apr 30 | — | May 28 – Jun 11 | — |
| Melons & Watermelon | Apr 23 – Apr 30 | Jun 4 – Jun 18 | — | — |
| Carrots | — | — | Apr 30 – May 28 | Jul 3 – Jul 17 |
| Beets | — | — | Apr 30 – May 28 | Jul 17 – Jul 31 |
| Potatoes | — | — | Apr 30 – May 21 | — |
| Swiss Chard | — | — | May 7 – Jun 4 | Jul 17 – Jul 31 |
| Cilantro | — | — | May 7 – May 28 | Jul 31 – Aug 21 |
| Green Beans | — | — | May 28 – Jun 18 | Jul 10 – Jul 24 |
| Sweet Corn | — | — | May 28 – Jun 11 | — |
| Sweet Potatoes | — | Jun 4 – Jun 25 | — | — |
| Garlic | — | — | — | Sep 11 – Oct 16 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Sundance, WY weather station, 2 km away (elevation 4,695 ft (1,431 m)).
Frost dates near Sundance
- Devils Tower May 23 · Sep 20
- Beulah May 17 · Sep 27
- Alva May 17 · Sep 23
- Moorcroft May 23 · Sep 20
- Upton May 20 · Sep 23
- Aladdin May 7 · Oct 3
- Hulett May 17 · Sep 23
- Four Corners May 13 · Oct 3
- Osage May 20 · Sep 23
- Newcastle May 13 · Oct 3
Frequently asked questions
When is the last frost in Sundance, WY?
The median last spring frost in Sundance, WY is May 21. There is still about a 10% chance of frost after June 5, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Sundance, WY?
The median first fall frost is September 25, with about a 10% chance of frost before September 7.
How long is the growing season in Sundance, WY?
About 127 days between the median last spring frost and first fall frost.
What planting zone is Sundance, WY?
Sundance, WY is in USDA hardiness zone 4b.